JPH1020029A - Object detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a direction (position) detecting device of object by one set of interrogator and transponder by providing a detecting means for detecting the existing direction of a detecting object or the direction of the detecting object from the correlation of transmitted signal and returned signal. SOLUTION: A receiving coil 12 and a transmitting coil 4 are formed on the pulse oscillator 3 of an interrogator 1 on the same axis or on the same core, and the windings are also arranged in the same direction. Both signals of transmitted wave and received wave are calculated by a multiplying computing element, and the direction (direction of a transponder 2) of the coil 6 of the transponder 2 is detected by a phase detector 13, and the difference of detected waveform is outputted to judge the necessity of expansion of an air bag. By use of either one of the positive side and negative side of the alternating voltage/current induced in the coil 6, Q of the coil 6 is interrupted by the internal resistance of a diode 14 to damp it. By working and retransmitting either one of positive side and negative side of the alternating voltage/current induced in the coil 6, the waveform of the voltage/current induced in a receiving coil 12 is varied according to the direction of the coil 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object detection device for detecting the position of a target object and the presence or absence of the target object, and more particularly to a question answering device (an interrogator and a transponder device) which detects electromagnetically. The present invention relates to an object detection device used.

[0002]

2. Description of the Related Art FIG. 15 is a block diagram showing a schematic configuration of a conventional question answering apparatus. 1 is an interrogator
A question signal transmitting unit (magnetic field generating unit on which a signal is superimposed) that transmits a transmission signal using magnetic force lines as a carrier medium for transmitting and receiving signals, and a response from a response device 2 in response to a transmission signal from the inquiry device 1 And a response signal receiving unit (response signal detecting unit) that receives the response signal to be received.

[0003] Reference numeral 2 denotes a transponder (transponder) which receives a transmission signal by magnetic field lines radiated from the interrogator 1,
The modulation is converted into another type of modulation, and the magnetic field lines are retransmitted to the interrogation device 1 again. As described above, the question answering device includes the questioning device 1 and the answering device 2, and the former is generally called the interrogator 1 and the latter is generally called the transponder 2.

An oscillator 3 has a frequency of about 100 k, for example.
A continuous sine wave signal is supplied to the coil 4 as necessary. Reference numeral 4 denotes a coil, which uses a magnetic core as necessary, and is wound so that an electric wire insulated with polyurethane or the like is wound many times, and most of the magnetic force lines generated from the coil 4 pass through the coil 6 of the transponder 2.

[0005] Reference numeral 5 denotes a signal detection unit, which includes an amplifier, a detector, an integrator, and the like, and is configured to detect the content of a response signal to which the transponder 2 responds (retransmits). Reference numeral 6 denotes a coil, and a magnetic core is used as necessary, and an electric wire insulated with polyurethane or the like is wound many times.
Is configured so that most of the magnetic lines of force generated from the coil 6 penetrate the coil 4 of the interrogator 1, that is, the reversible interaction between the coil 6 and the coil 4 is efficiently performed.

Reference numeral 7 denotes a capacitor using a metal-deposited paper capacitor or the like, which is connected in parallel with the coil 6 so as to resonate with the frequency of the oscillator 3 and generate received power efficiently. 8 is a resistor, such as a metal film resistor,
It is connected to the coil 6 via the switch 9 and is configured to attenuate the Q (Quality Factor) of the coil 6 while the switch 9 is closed.

Reference numeral 9 denotes a switch, which is constituted by a switching transistor or the like. The switching transistor is driven such that the switch 9 is turned on and off in accordance with a modulation signal output from the modulation driving unit 11. Reference numeral 10 denotes a rectifying unit, which is composed of a full-wave rectifying semiconductor diode or the like. The input side of the bridge circuit of the rectifying unit 10 is connected to both terminals of the coil 6, and the output side rectified and output by the bridge circuit is modulated. The modulation drive unit 11 is configured to be connected to the unit 11 and to supply power required for the modulation drive unit 11 to operate from the coil 6 via the rectification unit 10.

[0008] Reference numeral 11 denotes a modulation driving unit which is configured by a multivibrator circuit or the like using transistors, and is configured so that a modulation signal is formed by this circuit and supplied to the switch 9. Next, a principle operation in a case where the interrogator 1 and the transponder 2 are arranged close to each other and both are electromagnetically coupled will be described.

A continuous sine wave signal from an oscillator 3 in the interrogator 1 is connected to one terminal of a coil 4,
Is connected to the oscillator 3 via the signal detection unit 5 having a low internal impedance from the other terminal of the signal detection unit 5, and as if the output voltage of the oscillator 3 is applied to the impedance of the coil 4, the signal detection unit 5 detects the current A flowing through the coil 4. I do. The current A flowing through the coil 4 is induced by the coil 4 in the coil 6 in the transponder 2 which is electromagnetically coupled, and is caused by an induced voltage mutually induced in the coil 4 from the coil 6.

In the transponder 2, the interrogator 1
The coil 6 picks up a line of magnetic force alternating with a sine wave transmitted from the coil 4 of the coil 4, and a capacitor 7 connected in parallel with the coil 6 tunes the frequency of the sine wave to a parallel resonance circuit. Q of reception voltage
A voltage (effective Q of the coil) times appears at both ends of the coil 6 (when the switch 9 and the rectifier are open).

The received voltage induced in the coil 6 is rectified by the rectifier 10 and the rectified output is output to the modulation driver 1.
1, the modulation drive unit 11 switches off the switch 9 in a predetermined duty cycle, and as a result, the Q of the coil 6 changes according to the switch off of the switch 9, and the reception induced in the coil 6 is changed. The voltage changes. That is, the switch 9
The receiving voltage is amplitude-modulated by the disconnection operation.

The lines of magnetic force alternating according to the amplitude modulation voltage are sent out from the coil 6 as retransmission signals, become an induced voltage induced in the coil 4 of the interrogator 1, and are superimposed on the signal supply voltage from the oscillator 3, The signal is input to the signal detector 5. The signal detection unit 5 detects the input retransmission signal and detects an amplitude modulation component such as a modulation frequency (switching operation frequency of the switch 9).

Although the above is the case of the amplitude modulation method, there are other methods such as pulse modulation and frequency modulation.
There is also a medium that uses electromagnetic waves as a signal carrier medium. One of the applications of the question answering apparatus using the electromagnetic coupling described above is as to whether or not a child auxiliary seat (child seat) to be mounted on a front passenger seat of an automobile (with or without a child auxiliary seat) is provided. There is the question answering device which "detects" the mounting direction (whether the child auxiliary seat is facing forward or backward).

The reason why such "detection" is necessary is that the deployment of the airbag for safety protection of the occupant of the child seat when the vehicle collides is automatically prohibited, and the deployment must be performed. There is a case.
When the child seat is mounted in the same direction (forward direction) as the traveling direction of the vehicle, it is necessary to prepare for deployment of the airbag. On the other hand, when the child seat is mounted in the opposite direction to the traveling direction of the vehicle (children). If the back of the vehicle is mounted (facing backwards), the deployment of the airbag must be prohibited.

As seen in other countries, if the child seat is mounted backward, if the airbag is deployed, the backrest of the child seat is compressed by the airbag, and the occupant of the child seat. However, since there is a high possibility that a serious accident may be caused by this pressure, it is necessary to prohibit the operation of deploying the airbag. FIG. 16 is a view showing a conventional arrangement of the question answering apparatus for mounting the child seat on the passenger seat and detecting the mounting direction.

1A and 1B shown in FIG. 16 (a) show the two interrogators, and their mounting positions are mounted in the seating surface of the passenger seat diagram (a) (one end of the interrogator is black). , And the two units indicate one direction). Also, 2A and 2B shown in FIG. 2B are the two transponders, which are mounted on the bottom surface of the child seat diagram (B) (both in the same direction as indicated by hatching).

Each of the transponders has a different modulation frequency, and the demodulation detected and output by the interrogators 1A and 1B is determined by a combination as shown in FIG. When the frequency is detected and the child seed is attached to the vehicle in the reverse traveling direction (rotated by 180 ° with respect to the traveling direction), control is performed so that the airbag is not deployed (indicator on the instrument panel). Also shown).

[0018]

However, FIG.
In the conventional device for detecting the direction (position) of an object as shown in the application example, it is necessary to prepare two sets of interrogators and transponders, and there are problems in terms of cost and mounting space of the device. Further, when one set of the conventional interrogator and transponder is used, it can be determined whether or not the transponder is mounted (presence or absence), but the direction (position) cannot be detected.

Therefore, an object of the present invention is to realize an object direction (position) detecting device with a set of an interrogator and a transponder.

[0020]

According to the present invention, there is provided a transmitting / receiving means for transmitting / receiving an electromagnetic signal as a medium, and a transmission signal transmitted by the transmitting / receiving means being electromagnetically coupled to the transmitting / receiving means and transmitting a reply signal. An object detection device for detecting whether or not a sensing object to which the returning means is fixed is present in the vicinity of the transmitting / receiving means, wherein a direction of the presence of the sensing object is determined based on a correlation between the transmission signal and the return signal. Alternatively, a detection means for detecting the direction of the detection object is provided.

Further, the transmission signal transmitted by the transmission / reception means is a pulse wave, and the detection means includes phase detection means for detecting the phase of the return signal with the transmission signal. The transmission signal transmitted by the transmission / reception means is a pulse wave, and the detection means includes a polarity detection means for detecting a polarity of the return signal with respect to the transmission signal.

Further, the transmission signal transmitted by the transmission / reception means is a continuous wave, and the return means transmits a specified part of the transmission signal in synchronization with the transmission signal in the transmission signal received by the return means. An extraction means for extracting a return signal is provided, and the detection means includes a level detection means for detecting a detection signal level of the received return signal.

The transmitting signal transmitted by the transmitting / receiving means is a continuous wave, the retransmitting means is a waveform converting means for turning a received signal back into a continuous waveform having the same polarity, Retransmitting means for retransmitting the converted signal, wherein the transmitting and receiving means has level detecting means for detecting an amplitude detection signal level of the retransmitted converted signal. .

The transmission signal transmitted by the transmission / reception means is a continuous wave, and the transmission / reception means and the return means have a plurality of coils having different directions from each other. A reception signal having a different phase is obtained from a difference in the direction of the plurality of coils. Further, the detection object is fixed so as to be rotatable about a predetermined rotation axis on a predetermined plane, and the transmission signal transmitted by the transmission / reception means is a continuous wave, and the transmission / reception means includes electromagnetic coupling. Are arranged so that their axes are perpendicular to the plane, and in the return means, the plurality of serially connected coils for electromagnetic coupling have their axes parallel to the plane. And the return means is provided with a voltage difference detecting means for detecting a voltage difference between the electromotive forces generated in the plurality of coils and using the voltage difference as a transmission signal.

Further, the number of turns of the plurality of coils in the return means is different.

[0026]

Next, an embodiment of the present invention will be described. FIG.
FIG. 2 is a configuration diagram showing the configuration of the first embodiment of the present invention, and FIG. 2 is a waveform diagram showing signal waveforms of main parts during operation of this embodiment. The same circuit configuration as that of the conventional configuration shown in FIG. 15 is denoted by the same reference numeral, and detailed description is omitted.

The oscillator 3 shown in FIG. 1 is constituted by a pulse oscillator in this embodiment. A receiving coil 12 has the same structure as the transmitting coil 4 and is formed coaxially (or concentrically) with the coil 4 and has the same winding direction (shown by black dots).
It is. Reference numeral 13 denotes a phase detector, which is composed of a multiplying operation unit and the like. Both signals of the transmission wave and the reception wave are calculated, and the direction of the coil 6 of the transponder 2 (direction of the transponder 2) is detected by the phase detector. The air bag deployment controller is configured to determine whether or not the air bag deployment is necessary based on the difference between the two.

Numeral 14 denotes a diode which is composed of a silicon diode or the like, and which uses either the positive side or the negative side of the alternating voltage / current induced in the coil 6 to connect and disconnect the Q of the coil 6 by the internal resistance of the diode 14. To be attenuated. Alternating voltage induced in the coil 6 /
Processing and retransmitting either the positive side or the negative side of the current is characterized by the difference in the voltage / current waveform induced in the receiving coil 12 depending on the direction of the coil 6 (the direction of the transponder 2). .

The operation of this embodiment will be described. FIG. 2A shows a case where the transponder 2 is mounted in a “backward traveling direction” with respect to the traveling of the vehicle, and FIG. 2B shows a case where the transponder 2 is mounted in a “traveling direction” along the traveling of the vehicle. The respective waveforms in the case of the above are shown. The transmission waveforms (a) in FIGS. (A) and (B) are the same because the interrogator 1 is used as a reference.

The received waveform (b) at the transponder 2 is
According to the mounting direction of the transponder 2, the polarities are shifted by 180 ° in FIGS. This means that the direction of the coil 6 of the transponder 2 in FIG.
And the case where it is mounted in the "traveling direction" is different by 180 degrees. Next, the transponder processing waveform (c) is a waveform processed by the diode modulation of the transponder 2 and is one of the positive or negative waveform (FIG.
The negative decay is greatly attenuated.

The reception waveform (d) at the interrogator 1 is a reception waveform corresponding to the retransmission waveform of the transponder 2. Then, the interrogator 1 performs a multiplication operation of the received wave (a) and the transmitted wave (b), outputs an in-phase output of both waves as a phase detection waveform (e), and in the case of a positive output, the transponder 2 It means that the transponder 2 is attached in the traveling direction, and in the case of a negative output, it means that the transponder 2 is attached in the traveling direction.

As described above, according to the first embodiment, 1
By using a pair of interrogators and transponders,
The mounting direction (position) of the transponder can be detected. Next, a second embodiment of the present invention will be described. FIG. 3 is a configuration diagram showing the configuration of the second embodiment, and FIG. 4 is a waveform diagram showing signal waveforms during operation of the second embodiment.

The transponder 2 has the same construction and operation as the first embodiment, but in this embodiment, the interrogator 1 for detecting the mounting direction (position) of the transponder 2
Is characterized by a pulse polarity detection method for detecting the direction (positive / negative) of the pulse of the received wave. Fifteen
Is a polarity detector, which is composed of two pairs of comparators 31, a comparison signal source 32, and a one-shot multivibrator 33.

The received wave signal from the receiving coil 12 is input to the non-inverted input comparator (COMP1) and the inverted input comparator (COMP2), respectively, and the received wave signal larger than the comparison signal source (comparator threshold voltage) 32 is output. When input, each comparator outputs a signal to activate the next stage one-shot multivibrator. FIG. 4 shows the above signal waveforms.

FIG. 4 shows whether the received waveform (a) at the interrogator has a positive polarity or a negative polarity in each mounting direction of the transponder 2. In the case of the positive polarity, the comparator (COMP1) responds. Then, the output of the comparator (COMP1) output from the output terminal V1 of the one-shot multivibrator 33 appears as shown in the output waveform diagram (b).

On the other hand, when the received waveform (a) has negative polarity, the comparator (COMP2) is sensitive (COMP1 is not sensitive),
The output of the comparator (COMP2) output from the output terminal V2 of the one-shot multivibrator 33 appears as shown in the output waveform diagram (c). As described above, the mounting direction (position) of the transponder is detected depending on whether the output appears at one of the output terminals V1 and V2 of the two one-shot multivibrators 33.

As described above, according to the first and second embodiments, since it is possible to configure the conventional interrogator or transponder by adding only a few components, a significant cost reduction can be expected. Next, a third embodiment of the present invention will be described. FIG. 5 is a configuration diagram showing the configuration of the third embodiment, and FIG. 6 is a waveform diagram showing signal waveforms of respective parts during operation of the third embodiment.

The present embodiment is characterized by a synchronous modulation method (tentative name) for performing synchronous modulation on a received wave of the transponder 2, and a sine wave oscillator is used as the oscillator 3. An edge detection circuit 51 is composed of a high gain amplifier, a differentiating circuit, and the like. For example, a sine wave shown in the transponder reception waveform (b) of FIG. 6A is amplified through the high gain amplifier. Is saturated and a sine wave is clipped, and a rectangular wave is output. By passing this rectangular wave through a differentiating circuit, a differentiated pulse output is obtained. When the sine wave rises at the zero potential line (zero level) ) Approximately coincides with the moment of passing.

Reference numeral 52 denotes a one-shot multivibrator, which is composed of a transistor, a diode, and the like. The one-shot multivibrator is triggered by a differential pulse output of the rectangular wave (sensitive to either positive or negative polarity), and the sine wave passes through a zero level. At the moment, a pulse having a specified pulse width is output to the modulator 53. As described above, the modulation is performed so as to be synchronized with each sine wave, so that the modulation is tentatively called a synchronous modulation method.

Numeral 53 denotes a modulator composed of a transistor gate circuit and the like. The sine wave shown in the transponder reception waveform (b) is modulated by the output pulse of the one-shot multivibrator, and the modulation waveform (e) in FIG. Are performed and retransmitted. The illustration and description of the power supply circuit and the like for the edge detection circuit 51 and the one-shot multivibrator 52 are omitted.

Further, the modulator 53 can modulate an oscillator provided separately in the transponder 2 and retransmit the same. On the other hand, 5 which is one of the components of the interrogator 1
Reference numeral 4 denotes a polarity detection unit which is configured by an integrating circuit or the like, integrates a reception waveform induced in the coil 12 of the interrogator 1 shown in FIG. 6A or FIG. 6B, and outputs a determination output (g) of a negative voltage. Or the positive voltage, the mounting direction (position) of the transponder 2 is detected.

According to the third embodiment described above, since a sine wave is used as a transmission wave, interference with radio reception and electromagnetic interference with other electronic devices due to emission of harmonics or induction of the transmission wave is reduced. There are advantages. In addition, the magnitude of the energy of the retransmitted wave can be reduced by one digit or two or more digits as compared with the transmitted wave, and the harmonic energy that may cause interference can be reduced.

Next, a fourth embodiment of the present invention will be described.
FIG. 7 is a waveform diagram showing transmission / reception waveforms during operation of the fourth embodiment. The present embodiment is characterized by a phase modulation method for performing phase modulation on a received wave of the transponder 2, and a sine wave oscillator is used as the oscillator 3. In the transponder 2, a reactor or an inverting switch circuit for inverting the received wave every 180 degrees based on the received wave is configured to perform phase modulation (tentative name), and the phase modulation waveform (c) shown in FIG. It is configured to retransmit.

On the other hand, in the interrogator 1, the reverse traveling direction is shown in FIG. 7A and the traveling direction is shown in FIG. 7B based on the mounting direction (position) of the transponder 2. Is induced in the receiving coil 12. The induced voltage / current induced in the receiving coil 12 is detected by the polarity detection unit 54, and a determination output (e) for determining which direction (position) of the transponder 2 is in which direction.
Is output.

According to the fourth embodiment described above, the circuit for detecting the received waveform in the interrogator is simple, and a large signal-to-noise ratio can be obtained. Next, a fifth embodiment of the present invention will be described. FIG. 8 is a configuration diagram showing the configuration of the fifth embodiment, and FIG. 9 is a layout diagram showing the relative arrangement of the devices of the fifth embodiment.

In this embodiment, the coil 4 and the coil 6 are each divided into two and are wound, and the divided and wound coils are held in each device at right angles to each other as shown in FIG. It is configured to be. The splitters of the split coil 4 are denoted by a1 and a2, and the coil 6 is denoted by b1 and b2.
And the winding directions of the windings are the same,
The beginning (or end) of the winding is shown by black dots.

Then, among the divided winding coils incorporated in the interrogator 1 and the transponder 2, the vertically arranged coils a1 and b1 are arranged along the same axis (indicated by a dashed line) and horizontally. The coils a2 and b2 are arranged so as to be parallel (shown in FIGS. A and B), and so that both coils are closest. Reference numeral 81 denotes a phase difference detecting and modulating means, which receives a wave received by the divider (coil) b1 and a divider (coil) b2 based on a junction between the dividers (coils) b1 and b2 of the coil 6.
And a modulation means for modulating the phase of the retransmitted wave to be retransmitted based on the detected phase difference.

Reference numeral 82 denotes a detecting means for detecting the direction (position) of the transponder 2 based on a composite wave of a retransmission wave arriving from the transponder 2 induced in the coil 12 of the interrogator 1 and a transmission wave transmitted by the interrogator 1. It consists of detecting means. FIG. 9 shows a case where the transponder 2 is attached to the interrogator 1 in the backward traveling direction (shown in FIGS. A and C) and a case where the transponder 2 is attached in the traveling direction (shown in FIGS. B and D). Shows the arrangement of opposing coils facing each other.

In the example of FIG. 9, FIGS. A and C (reverse traveling directions)
In this case, the coil a1 and the coil b1 are coaxially opposed to each other, and the coil a2
And the coil b2 are opposed in parallel and all have the same winding direction, so that mutual induction of the coils is effectively performed. On the other hand, FIG.
In the case of FIG. D (traveling direction), the opposing condition of the coils a1 and b1 is the same as in the case of FIGS. A and C, but the coils a2 and b2 oppose in the opposite directions. Therefore, mutual guidance is partially canceled.

As described above, since the coil 4 and the coil 6 are dividedly wound and the arrangement of the coils is defined, the signal retransmitted by the transponder 2 becomes clear according to the direction (position) of the transponder 2. Therefore, the mounting direction (position) of the transponder 2 can be detected. Next, a sixth embodiment of the present invention will be described.

FIG. 10 is a block diagram showing the configuration of the sixth embodiment, and FIGS. A and B show two embodiments. In the present embodiment, the split winding coil 6b1, which is a component of the transponder 2,
6b2 relates to a method of processing an induced voltage induced in response to a transmission wave transmitted from the indrogator 1.

The configuration and structure of each coil of the interrogator 1 and the transponder 2 are the same as those shown in FIGS. 8 and 9, and a description thereof will be omitted. First, a description will be given with reference to FIG. Reference numeral 83 denotes a detection diode, which is composed of a silicon diode or the like. The alternating voltage induced in the divided winding coils 6b1 and 6b2 is detected, and a rectified voltage corresponding to the induced voltage is output and input to the comparator 31.

Reference numeral 84 denotes a smoothing capacitor, which uses a film capacitor or the like, smoothes the pulsating output voltage from the detection diode 83, and holds a DC voltage for a specified time (forms a time constant with the input resistance of the comparator 31). . Reference numeral 31 denotes a comparator, which is composed of a semiconductor integrated circuit including an operation amplifier circuit, receives a DC output voltage from the detection diode 83, compares this input with a comparison voltage 32,
A signal output according to the input is supplied to the modulator.

The induced voltages induced in the coils 6b1 and 6b2 are rectified by the respective diodes 83, and their DC outputs are input to the comparators 31. The outputs of the comparators are connected in parallel. The outputs are combined, output as a voltage difference corresponding to the voltage induced in the coils 6b1 and 6b2, and modulated (the description of the modulation is omitted).

This voltage difference becomes zero when the transponder 2 is mounted in the backward traveling direction, and a voltage difference appears when the transponder 2 is mounted in the traveling direction, so that the mounting direction (position) can be distinguished. According to the embodiment shown in FIG.
Each of the two comparison voltages 32 is configured to be variably adjusted so that each comparator 31 operates in accordance with the input level or the like, and by performing this initial adjustment setting,
Variations in the voltage induced in the divided coils 6b1 and 6b2 can be absorbed.

Therefore, if the variable comparison voltage 32 is used, the degree of freedom with respect to the mounting positions of the interrogator 1 and the transponder 2 is large, and the present invention can be applied to various types of mounting sheets. Next, in FIG. B, the voltages induced in the two split winding coils 6b1 and 6b2 are directly input to the non-inverting input terminal and the inverting input terminal of the comparator 31, respectively.

Then, a voltage difference corresponding to the two voltages induced in the two coils 6b1 and 6b2 is output from the comparator 31 and modulated (the description of the modulation is omitted). This voltage difference becomes zero when the transponder 2 is mounted in the traveling direction, and a voltage difference appears when the transponder 2 is mounted in the backward traveling direction, so that the mounting direction (position) of the transponder 2 can be detected.

According to the embodiment shown in FIG. B, since the circuit is simple and the number of parts used is small, the size and cost of the apparatus can be reduced. Next, a seventh embodiment of the present invention will be described. FIG.
FIG. 12 is a configuration diagram showing a configuration of the seventh embodiment, and FIG. 12 is a waveform diagram showing an internal waveform of the transponder of the present embodiment.

The present embodiment relates to a method of processing an induced voltage induced in response to a transmission wave transmitted from the indrogator 1 in divided winding coils 6b1 and 6b2, which are components of the transponder 2. In addition, interrogator 1
The configuration and structure of each coil of the transponder 2 are the same as those shown in FIGS. 8 and 9, and the description is omitted.

Reference numeral 85 denotes a vector addition means, which is composed of a circuit using a differential amplifier or the like, and calculates and outputs the sum of two input signals. When the induced voltages Vb1 and Vb2 induced in the coils 6b1 and 6b2 are input to the vector adding means 85, the vector sum of the two voltages is output and supplied to the modulator. These voltage waveforms will be described with reference to FIG.

When the mounting direction of the transponder 2 is the reverse traveling direction (FIG. A) and the traveling direction (FIG. B), Vb1
(Fig. A) has the same (same homologous amplitude), but Vb2 (Fig. B) has the same amplitude, but the phase is shifted by 180 °. Accordingly, the sum Vout of Vb1 and Vb2 in the reverse traveling direction is output with a double amplitude, while the sum Vout of Vb1 and Vb2 in the traveling direction is zero output.

As described above, the detection output is clearly divided according to the mounting direction of the transponder 2 by using a simple circuit, so that the direction can be reliably detected. Next, an eighth embodiment of the present invention will be described. FIG. 13 is a configuration diagram showing the configuration of the eighth embodiment. In the present embodiment, the split winding coils b1 and b2 of the coil 6, which is a component of the transponder 2,
The number of turns of each winding of the coil b1 and the coil b2 is changed for each division unit.

For example, if the turns ratio of the windings of the coil b1 to the coil b2 is 1: 2, the induced voltage induced in response to the transmission wave from the interrogator 1 is Vb1 volt in the coil b1, and Vb2 in the coil b2. A volt is induced and the voltage ratio is 1: 2. Reference numeral 86 denotes an induced voltage processing and modulation means, for example, using the same method as any one of the fifth, sixth and seventh embodiments.

FIG. 14 is a voltage vector diagram showing a model of an induced voltage induced in the receiving coil 12 of the transponder 1 using the transponder of this embodiment. When the transponder 2 is mounted in the reverse traveling direction, the induced voltage is the same for the coil b1 and the coil b2, and the voltage composite value is as follows. On the other hand, when the transponder 2 is mounted in the traveling direction, the induced voltage of the coil b2 is-(the opposite direction of 180 degrees) to the coil b1, and the combined voltage value is-.

When the transponder 2 (the child seat) is not mounted on the interrogator 1 (the passenger seat), the retransmitted wave component retransmitted from the transponder 2 does not exist, so that the voltage composite value becomes zero. According to the above-described embodiment, by changing the number of turns of each winding of the divided winding coil for each division unit, the detection output is clearly divided according to the mounting direction of the transponder 2, so that a reliable direction detection can be performed, It is not necessary to use special parts, and it is possible to reduce the size and cost.

As described above, according to the present invention, in the relative direction or relative position between the transponder mounted on an object whose direction or position is to be detected and the interrogator, the transponder
Emits a characteristic (easy to separate) retransmit signal according to the relative direction (position), and detects this characteristic (easy to separate) retransmit signal with an interrogator (interrogator). Therefore, it is possible to realize a question answering apparatus capable of detecting the direction or position of an object with a set of question answering apparatuses.

[0067]

As described above in detail, according to the present invention, it is possible to realize an object detecting device capable of detecting the presence / absence and direction of an object with a question answering device including a set of an interrogator and a transponder. is there.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a waveform chart showing transmission / reception waveforms according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram showing a configuration of a third embodiment of the present invention.

FIG. 4 is a waveform chart showing transmission / reception waveforms according to a second embodiment of the present invention.

FIG. 5 is a configuration diagram showing a configuration of a third embodiment of the present invention.

FIG. 6 is a waveform chart showing transmission / reception waveforms according to a third embodiment of the present invention.

FIG. 7 is a waveform chart showing transmission / reception waveforms according to a fourth embodiment of the present invention.

FIG. 8 is a configuration diagram showing a configuration of a fifth embodiment of the present invention.

FIG. 9 is an arrangement diagram showing a relative arrangement of a fifth embodiment of the present invention.

FIG. 10 is a configuration diagram showing a configuration of a sixth embodiment of the present invention.

FIG. 11 is a configuration diagram showing a configuration of a seventh embodiment of the present invention.

FIG. 12 is an internal waveform diagram of a transponder according to a seventh embodiment of the present invention.

FIG. 13 is a configuration diagram showing a configuration of an eighth embodiment of the present invention.

FIG. 14 is a vector diagram of an induced voltage according to the eighth embodiment of the present invention.

FIG. 15 is a configuration diagram showing a conventional configuration outline.

FIG. 16 is a diagram showing the structure and arrangement of a conventional direction detection example.

[Explanation of symbols]

 1 Interrogator 2 Interrogator 3 Transponder 3 Oscillator 4 Coil 5 Signal detector 6 · Coil 7 ······ Capacitor 8 ····· Resistor 9 ··· Switch 10 ··· Rectification unit 11 ··· Modulation drive unit 12 ··· Receiving coil 13 ··· · Phase detector 14 · · · Diode 31 · · · Comparator 32 · · · Comparison signal source 33 · · · One shot multivibrator 51 · · · Edge detection circuit 52 · · · One shot multivibrator 53 ··· Modulator 54 ··· Polarity detection section 81 ··· Phase difference detection and modulation means 82 ··· Detection means 83 ··· Detection diode 84 ··· Smoothing capacitor 85 ··· .Vector voltage adding means 6 .... induced voltage processing modulation means

Claims (8)

[Claims] 1. A transmission / reception means for transmitting / receiving an electromagnetic signal as a medium, and a return means for electromagnetically coupling with the transmission / reception means, receiving a transmission signal transmitted by the transmission / reception means and transmitting a return signal, An object detection device for detecting whether a detection object having a fixed return means is present near the transmission / reception means, wherein an existence direction of the detection object or a direction of the detection object is detected from a correlation between the transmission signal and the return signal. An object detection device, comprising: a detection unit that performs detection. 2. The transmission signal transmitted by the transmission / reception means is a pulse wave, and the detection means has a phase detection means for performing phase detection of the return signal with the transmission signal. Object detection device. 3. The transmission signal transmitted by the transmission / reception means is a pulse wave, and the detection means has a polarity detection means for detecting a polarity of the return signal with respect to the transmission signal. The object detection device according to claim. 4. The transmission signal transmitted by the transmission / reception means is a continuous wave, and the return means transmits a specified part of the transmission signal synchronized with the transmission signal in the transmission signal received by the return means. 2. The object detection device according to claim 1, further comprising: an extraction unit that extracts a return signal, wherein the detection unit includes a level detection unit that detects a detection signal level of the received return signal. 5. The transmission signal transmitted by the transmission / reception means is a continuous wave, the return means is a waveform conversion means for turning a reception signal back into a continuous waveform having the same polarity, and the waveform is converted by the waveform conversion means. Returning means for returning the converted signal, wherein the transmitting / receiving means includes level detecting means for detecting an amplitude detection signal level of the returned converted signal. Object detection device. 6. The transmission signal transmitted by the transmission / reception means is a continuous wave, wherein the transmission / reception means and the return means have a plurality of coils having different directions, and 2. The object detection device according to claim 1, wherein reception signals having different phases are obtained from differences in the directions of the plurality of coils. 7. The detection object is fixed on a predetermined plane so as to be rotatable around a predetermined rotation axis, and the transmission signal transmitted by the transmission / reception means is a continuous wave. A coil for electromagnetic coupling is arranged such that its axis is perpendicular to the plane, and in the returning means, a plurality of serially connected coils for electromagnetic coupling have their axes relative to the plane. Wherein the return means detects a voltage difference between electromotive forces generated in the plurality of coils, and includes a voltage difference detection means which uses the voltage difference as a transmission signal. Item 1. The object detection device according to Item 1. 8. The object detection device according to claim 6, wherein the number of turns of the plurality of coils in the return means is different.